Properties: Efflorescent crystals or powder; bitter, saline, cooling taste. d 1.67. Soly in water (g/100 ml): at 20° = 71; at 40° = 91. Slightly sol in alcohol. Its aq soln is neutral. pH 6-7. On exposure to dry air at ordinary temp it loses ~1H2O; at 70-80° loses 4H2O; at 100° loses 5H2O; at 120° loses 6H2O, rapidly reabsorbing water when exposed to moist air; loses the last mol of water at ~250°.

Density: d 1.67

Derivative Type: Dried magnesium sulfate

Literature References: Prepd by heating the heptahydrate until ~25% of its weight is lost. Used in Morison's paste.